Folding screen for light permeable skylights and the like

ABSTRACT

A folding screen formed by a plurality of successively hinged, rigid, radiation-controlling panels supported for horizontal, planar movement in a pair of parallel, overhead tracks and operated by a flexible drive member extending along the track and connected to the lead panel. Since each panel is supported in the tracks only at its ends, each panel must possess sufficient rigidity to permit hinged, side-by-side coaction of interconnected panels from a stacked, generally vertical relationship to a generally horizontal, planar relationship. To enable the screen to be collapsed from an extended planar position without jamming, alternate hinges are vertically upwardly displaced. In a particular embodiment the hinges are provided with rollers at the ends thereof. Rollers for the lower and upper hinges travel in lower and upper levels, respectively, of each overhead track. A particularly useful elongated panel for a radiation screen under a light-permeable building component comprises an arcuate extrudate bounded at the sides by relatively thick discontinuous ribs, each of sufficient thickness to have an axial bore adapted to journal a rod for hingedly connecting adjacent panels for horizontal, side-by-side coaction from a collapsed, distensible stack of plural panels into an extended, collapsible radiation screen, and vice versa.

Gates Dec. 9, 197 5 [76] Inventor: Charles R. Gates, 15070 Hill Drive,

Novelty, Ohio 44072 [22] Filed: Mar. 5, 1975 [21] Appl. No.: 555,365

Related US. Application Data [63] Continuation-impart of Ser. No.462,172, April 18,

1974, which is a continuation of Ser. No. 242,649,

April 10, 1972.

[52] US. Cl 160/183; 160/206 [51] Int. Cl. EOSD 15/26 [58] Field OfSearch 160/133, 174, 183, 188,

[56] References Cited UNITED STATES PATENTS 2,505,155 4/1950 Smith49/371 2,561,206 7/1951 Kasper 160/229 2,839,135 6/1958 Anderson.160/133 3,219,101 11/1965 Prehn 160/193 3,265,117 8/1966 Lorentzen160/174 3,333,621 8/1967 Elder 160/206 3,348,516 10/1967 Caillet 160/188Primary ExaminerKenneth Downey Attorney, Agent, or Firm-Alfred D. Lobo[57] ABSTRACT A folding screen'formed by a plurality of successivelyhinged, rigid, radiation-controlling panels supported for horizontal,planar movement in a pair of parallel, overhead tracks and operated by aflexible drive member extending, along the track and connected to thelead panel. Sinceeach panel is supported in the tracks only at its ends,each panel must possess sufficient rigidity to pennit hinged,side-by-side coaction of interconnected panels from a stacked, generallyvertical relationship to a generally horizontal, planar relationship. Toenable the screen to be collapsed from an extended planar positionwithout jamming, alternate hinges are vertically upwardly displaced. lna particular embodiment the hinges are provided with rollers at the endsthereof. Rollers for the lower and upper hinges travel in lower andupper levels, respectively, of each overheadtrack.

A particularly useful elongated panel for a radiation screen under alight-penneable building component comprises an arcuate extrudatebounded at the sides by relatively thick discontinuous ribs, each ofsufficient thickness to have an axial bore adapted to journal a rod forhingedly connecting adjacent panels for horizontal, side-by-sidecoaction from a collapsed, distensible stack of plural panels into anextended, collapsible radiation screen, and vice versa.

4 Claims, 10 Drawing Figures U.S. Patent Dec. 9, 1975 Sheet 3 of53,924,671

FIG. 6

US. Patent Dec. 9, 1975 Sheet 4 of5 3,924,671

US. Patent Dec. 9, 1975 Sheet5 of5 3,924,671

FOLDING SCREEN FOR LIGHT PERMEABLE SKYLIGHTS AND THE LIKE CROSSREFERENCE TO RELATED APPLICATIONS This patent application is acontinuation-in-part application of Ser. No. 462,l 72 filed Apr. 18,1974 which in turn is a continuation application of Ser. No. 242,649filed Apr. 10, 1972.

BACKGROUND OF THE INVENTION This invention relates to a folding,horizontally disposed screen, useful in conjunction with transparent andtranslucent skylights and roof panels of various types, through whichheat generated by the suns rays and sunlight particularly in the rangefrom about the near-infrared to about the near-ultra-violet regions, maybe controlled. Until recently, the problem of controlling sunlight andheat transmitted through roof structures has been of interest mostly ingreen houses where the optimum growth of plants is governed by theskilled control of the intensity of light to which they are exposed. Inother applications, such as those in which skylights are used fordwellings, office buildings, and the like, the problem has beenrelatively less pressing, if only for the reason that the popularity ofskylights, and other transparent and translucent buildingroof-structures, has acquired momentum only in recent years.

The present ready availability, at reasonable cost, of relatively largetransparent planar and arcuate sections, generally referred to asbubbles, has increasingly prompted builders to use relatively largeexpanses of bubbles to provide a functional roof-structure open to thesky. Thus, bubbles formed from synthetic, resinous, plastic materials,as well as from glass and fiberglass laminates, are increasingly used inmodern residential and office buildings, including commercialinstallations for stadium roofs, service station island canopies,swimming pool enclosures, and the like. Mushrooming popularity ofbubbles and light-transmitting roof structures has created a demand foran effective, easy to operate, and reliable radiation screen. Above all,a radiation screen useful in such an application must be as functionalas it is compatible with the design and construction of the roofstructure. The radiation screen of this invention is directed tosatisfying that demand.

SUMMARY OF THE INVENTION The present radiation screen is directed foruse in conjunction with parallel, horizontal overhead tracks disposedbeneath a skylight or other transparent or translucent roof structure.It is a folding screen formed of a plurality of hingedly connected,elongated, rigid, light-controlling panels supported in the overheadtracks. The panels may be stacked in a generally vertical, collapsedstructure, or extended into a generally horizontal, planar structurebeneath the skylight to control the amount of radiation which passesfrom the skylight to the area below the screen. One end panel adjacentone end of the tracks is fixedly disposed for pivotal movement about alongitudinal edge and the lead panel is connected to a flexible cable orsimilar drive means, preferably in a closed loop, which is subjected tosufficient force either to pull the screen into an extended positionbetween one end of the tracks and the other, or to pull the screen in astacked, collapsed position. Where the bubbles or skylights are inclinedfrom the horizontal, the radiation screen may be supported in overheadtracks inclinedly disposed beneath the light-permeable sections. In aspecific embodiment, a radiation screen formed of plural, hingedlyconnected, rigid, light-controlling panels is supported for translationat an angle less than about from the horizontal, in overhead tracksintegral with the support structure for roof skylights. Hinges of allpanels are provided with roller means at each end, which roller meanspermit to-and-fro translation of the panels in the tracks when actuatedby a pull-cable.

Since rigidity of the panels is essential, the elongated panels arestiffened. Stiffness or rigidity may be imparted by ribs along thelength or across either the top or the bottom surface of the panels.More preferably, rigidity may be obtained by providing a gentle arc to apanel by displacing the longitudinal edges of each panel downwardly withrespect to the longitudinal axis along the upper surface of the panel.In other words, viewed from beneath, each panel is arcuate, beingconcave along its length. In one embodiment, plural, arcuate panels,collapsed in hinged, side-by-side relationship, present in end view, acompact profile of upstanding wishbones. In another embodiment thecollapsed screen presents a serrated profile which is even more compact.Rigidity of the panels is enhanced by relatively thickened ribs at thelongitudinal edges of the panels. The ribs are discontinuous and areprovided with an axial, horizontal bore; the discontinuations of adiscontinuous rib are adapted to accommodate a corresponding,juxtapositioned, discontinuous rib of an adjacent panel in a manner soas to permit a rod to be journaled therethrough. Interlocking ribs ofadjacent panels, with the rod journaled therein, form a succession ofhinges. In one embodiment of the invention each alternate rod isprovided with a roller at each end, the remaining rods being providedwith a washer at each end. In another embodiment all the rods areprovided with a roller at each end. Each of the overhead tracks isespecially adapted to permit translation of the panels, supported asdescribed hereinafter, on the tracks.

In the illustration described, a folding radiation screen is providedbeneath a transparent bubble of a plastic material such asmethyl-methacrylate or the like. The edges of the bubble are fixedlydisposed upon a horizontal support beam provided with an integral trackin which the rollers on one side of the radiation screen are guided.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front elevational view ofa rectangular bubble skylight;

FIG. 2 is an enlarged side elevational view along the line 22 in FIG. 1showing the support column on which the rectangular bubble is disposed,and a radiation screen in a collapsed or closed position, supported in atrack which is an integral part of the support beam;

FIG. 3 is a side elevational view diagrammatically illustrating theradiation screen which is partially extended in a horizontal, planarattitude, and partially in a collapsed position;

FIG. 4 is a side sectional .view along the line 4-4 in FIG. 2 withportions broken away to show details of 7 construction;

FIG. 5 is a plan view, partially broken away, along the broken plane 55in FIG. 4;

FIG. 6 is an end elevational view of an individual panel; and

FIG. 7 is a side sectional view with portions broken away showing thelead panel and the next preceding panel, and details of an installationof the instant folding screen in an existing structure having alight-permeable roof;

FIG. 8 is an elevational view similar to that shown in FIG. 2, ofanother embodiment of the invention showing the screen in an open orextended position in a bilevel overhead track;

FIG. 9 is an elevational view similar to that shown in FIG. 2, of theembodiment shown in FIG. 8, diagrammatically illustrating the radiationscreen in a collapsed position;

FIG. 10 is a side sectional view, similar to FIG. 4, with a portionbroken away, to show details of the embodiment shown in FIGS. 8 and 9,and particularly the bi-level track.

DETAILED DESCRIPTION OF THE INVENTION Referring to the drawings, FIG.l7, which illustrate one embodiment of the invention, FIG. 1 shows alarge rectangular bubble skylight shown generally as 10, removablyclamped on a horizontal support beam, shown generally as 20, disposedupon an upstanding wall 40. Similar support beams are horizontallydisposed beneath each outer edge of a bubble. Where plural bubbles areused in side-by-side relationship to form a bubble-roof, suitableintermediate support beams, not necessarily of the same configuration asthe support beams to be used also to support a foldable radiant screen,may be used. Where a large expanse of lighttransmitting roof, such as aroof for a concert hall, sports arena, or the like is to be screen,plural screens in generally side-by-side relationship may be used,suitably supported either on support beams with integral guiding tracksor on guiding tracks alone, where support of the roof-structure iseffected by other means, not in combination with a folding radiantscreen.

As is shown in FIG. 2, the rectangular bubble 10 includes flanged edge12 adapted to be clamped between suitably gasketed members of thehorizontal support beam 20, as will be described hereinafter. Thesupport beam includes a lower support section, referred to generally as21, and an upper clamping section 22. The upper section 22 is agenerally rectangular L-shaped elongated section, with a thickenedsection near one edge suitably adapted to secure a gasket 23 in aposition directly above the flanged edge 12 of the bubble. The uppersection 22 is adapted to be disposed exteriorly of a protruding.I-shaped section 24 on the outside of the lower support section 21 andon the upper portion thereof, so as to permit the member 22 to beclampingly secured upon the edge 12 by a fastening means such as a screw25. The edge 12 of the bubble 10 rests upon a gasket 26 removablysecured on top of the web of the lower support section 21. The gasket 26is removably disposed in an inverted T-shaped slot provided in the topof the lower support section 21. The base of the lower support section21 includes a horizontal track 27 provided with a vertical guiding lip28, the track 27 being disposed interiorly of the support section 21.Disposed exteriorly of the support section 21, the base includes adown-turned flange section 29 adapted to snugly fit the outside uppercorner of the wall 40. Disposed above the track 27 and inclinedlyprotruding interiorly from the support section 21 is a condensate gutter30. The entire lower support section 21, including the J-shaped section24, the track 27, the

down-turned flange 29 and the condensate gutter 30 are preferably formedas a single extrudate of aluminum. Where separate support beams are usedfor the roof structure; or in the case of pre-existinglight-transmitting structures, channel guides may be used separately toprovide suitably disposed tracks for the screen.

It will be apparent from the foregoing particular description thatwhere, as in new construction, the specially adapted two-part supportbeam 20 of this invention is used, the edge 12 of the bubble 10 issecurely clamped between the gaskets 23 and 26 which provide afluid-tight seal. The seal is maintained by securing the clampingsection 22 to the J-shaped section 24 by any suitable means such asplural metal screws 25.

Referring further to FIG. 2, and to FIG. 5 as required, the foldingradiation screen of this invention includes a pivot panel 50 and a leadpanel 51 connected by a series of intermediate panels 52, all shown in avertically upstanding, stacked or collapsed position. The verticalpanels 50-52 are successively connected together for side-by-sidecoaction by hinges 60 arranged successively on opposite sides of thepanels. The panels are maintained in stacked, vertical relationship by abiasing force exerted by spring means such as a spring 73, one end ofwhich is hooked into an eye bolt 74 fixedly disposed in the lowersupport section 21, near its base. The other end of the spring 73 ishooked into a lug 75 which is part of a pulley yoke 76. The springconstant of the spring 73 is such that it exerts sufficient force totake up any slack in a driven cable 69 which may normally be expected toresult from repeated opening and closing of the screen over an extendedperiod of time. It will be recognized that where the screen is to extendlongitudinally over a relatively long distance, a slight extension orcontraction of a metal cable cannot be disregarded. Where it ispractical to use other drive means, such as a chain, to translate thepanels from a stacked relationship to an extended, generally planarrelationship, the biasing means may be dispensed with.

The pulley yoke 76 has a pin 77 journaled in the arms of the yoke. Adrive pulley 78 and a driven pulley 80 are fixedly disposed inside-by-side relationship on the pin 77. The pulleys 78 and 80 arepreferably grooved to accommodate a drive cable 79 and the driven cable69. The drive cable 79 hangs downwardly through an aperture 81 providedin the track 27 and is preferably looped around an idler pulley (notshown) as is conventionally done, where manual operation of the drivecable is desired. Power drive means also may be conveniently adapted todrive the drive cable 79. As diagrammatically illustrated in FIG. 5, thedriven cable 69 is fixedly attached to a flared guide 67 on a lead wheel31 of a lead panel 51. Reverting to FIG. 2, it is seen that the cable 69thereafter is passed over an idler pulley (not shown) and returned so asto form a closed loop to open and close the folded screen. In theembodiment described herein, a drive cable and driven cable provided onone side of the screen, is sufficient to translate it in its tracks.Where relatively long panels are used, as for example, where each panelis in excess of 8 feet long, it may be desirable to provide a dual cablesystem, properly synchronized to extend or collapse the screen withoutjamming it in its tracks.

Each of the intermediate panels 52 are supported on intermediate wheels32 which ride on the track 27. The intermediate wheels 32 are secured onrods 66 of alternate hinges so as to align all the wheels 32 and 31, and

the alignment is maintained by providing nuts 82 for each wheel in sucha way as not to interfere with the operation of the driven cable 69.

As shown in FIGS. 3 and 4, each hinge 60 is formed by the rod 66journaled in mating discontinuous sections of ribs of adjacent panels.Referring now to the lower hinge 60, referred to as 60 in FIG. 4, it isseen that the rod 66 clears the vertical lip 28 on the inside edge ofthe track 27. The wheel 31 on the lead panel 51 is rotatably disposednear the end of the rod 66 and is supported by the track 27 for rollingtranslation thereupon. The end of the rod 66 protruding through thewheel 31 is provided with a flared guide 67 having a passage 68 throughwhich a cable 69 may be threaded but which is fixedly disposed withrespect to the guide 67 at the passage 68. Referring now to the upperhinge 60, referred to as 60" in FIG. 4, the rod 66 is provided at eachend with a washer 70 abuttingly secured against the ends of the matingribs 62 and 63 by a lock washer 71 and a nut 72. The dimensions of thewasher 70 are so chosen that, when the radiant screen is extended oropened, the washer 70 is peripherally supported against the upper edgeof the lip 28 maintaining the rods 66 of the hinges 60" in a generallyhorizontal plane. It will be recognized that, were the rod 66 in a hinge60 to fall below the horizontal plane defined by the rods 66 in thehinges 60' in the open position, the radiant screen could not be closed,that is, returned to its stacked position by a pulling action on thelead panel 51 to which the cable 69 is secured. The relationship of theaxis of the washers 70, slightly vertically displaced upwardly from theline connecting the axes of the wheels 31 and 32, is critical to permitcollapsing of the screen. The arcuate shape of each panel 5052,described hereinbelow, is a simple and easy way to impart longitudinalrigidity to the panels to facilitate operation of the screen.

As is shown in FIGS. 2 and 3, the pivot panel 50 is pivotally disposedabout a rod 66 journaled in brackets 90 fixedly disposed adjacent eachend of the overhead tracks 27. It will be recognized that each track 27on each side of the screen supports intermediate wheels 32 and a leadwheel 31 rotatably disposed on rods 66 of alternate hinges 60 so thatone end of each panel, on each side of the screen, is supported forrolling translation. Generally, a screen will extend longitudinallybeneath the full length of the skylight. In a fully collapsed position,the screen will permit all the radiant energy, both heat and light, toenter the enclosed structure. In a fully extended position, depending onthe choice of the light-permeability of the panels of the screen, theheat and light energy of the radiation through the skylight is screenedout to the extent desired. It will be apparent that the width ofindividual panels and the length of the light-permeable roof structurewill determine the number of panels required to furnish a screenadequate for the entire length. Where desirable, the folding screen mayalso be partially extended, leaving some panels stacked and distendingothers to provide a screen.

It is seen, that to open the radiant screen, that is, to extend thepartitions from a stacked position to a generally horizontal, planarposition, a pulling action on the lead panel 51 by the cable 69 willsequentially unfold the panels 5052 as the wheels 31 are rollinglytranslated along the track 27 and alternate hinges 60 of those panels inthe open position will, because of the washer 70, come to rest in aposition which will facili- 6 tate the re-stacking of the panels by apulling action on the cable 69 in a direction opposite to that requiredto extend the panels from a vertical stacked relationship.

As is shown in FIG. 6, each panel comprises an arcuate, elongated strip61 bounded at its edges by thickened, longitudinally extending ribs 62and 63, each provided with an axial bore for its entire length. The ribs62 and 63 are discontinuous to provide a hinge between adjacent panelswhen a rod 66 (FIGS. 2-5) is journaled therein. The strip and ribs ofeach panel are preferably extruded together from a suitable plasticmaterial such as methyl-methacrylate or other acrylic ester. Thediscontinuations or notches in each rib may be provided by shearingsections of each rib so as to permit discontinuous ribs of adjacentpanels to be interdigitated to form a hinge when the rod 66 is journaledin their aligned axial bores. Alternatively, the arcuate strip may beextruded or shaped by pressing, vacuum forming or the like, and the ribs62 and 63 affixed to the edges by solvent welding, sonic welding orother known methods. Fixing the ribs on to pre-formed strips isadvantageous where relatively short ribs will provide adequate hingingaction and support; but short ribs may require the edges of the stripsto be stepped to preclude undesirably wide open slots between successivepanels when the folding screen is fully extended.

The length and width of each panel is limited only by practicalconsiderations. For example, very long panels tend to sag in the centerand interfere with the smooth operation of the hinges. The deflection oflong panels may be overcome by increasing their rigidity either bymaking them more arcuate, by providing additional stiffening ribs or byutilizing a thicker cross-section of panel. It will be apparent thateach of the methods of increasing the rigidity presents certaindisadvantages with respect both to collapsing the screen tightly as wellas to economic feasibility. The width of the panels will be determined,inter alia, by the space available beneath the bubble, which in a newstructure utilizing the support beam 20 with integral, horizontal tracks27 of this invention, will depend upon the height of the lower section21 of the support beam 20. A convenient width of a strip for a panelparticularly suited to an essentially maintenance-free radiant screen,is in the range from about 3 to about 12 inches and a length from about4 to about 16 feet. Thickness of each strip is in the range from about0.0625 inch to about 0.375 inch. The ribs 62 and 63 may be convenientlyformed with a nominal or effective diameter in the range from about0.1875 inch to about 0.5 inch. It will be recognized that, where thewidth and length of a panel is such as to provide sufficient rigiditywithout necessitating an arcuate strip a flat, elongated strip may beused. The materials from which panels of predetermined radiationpermeability may be made are not limited to extruded plastic materials.The panels may be made of translucent fiberglass reinforced plasticpanels or from tinted glass. However, the ease with which glass may beextruded, formed and tinted is offset by the difficulty of handling it.By predetermined radiation. permeability is meant a preselected,desirable characteristic of the material from which the panel is formed,both with respect to the intensity and the range of wave lengths of heatand light radiation to which the panel is permeable.

As has been mentioned hereinabove, the folding radiation screen of theinstant invention may be used in existing structures withlight-permeable roofs. A partial section of a flat, light permeablebubble, as installed in an existing structure, is shown in FIG. 7 andincludes a sheet of tinted plastic material 10a clamped in a prior artsupport beam 20a. The upper portion of the support beam 20a is identicalwith the upper portion of the support beam 20. The lower portion of thebeam 20a is provided with a gutter 30a and a downwardly turned flangesection 11 at its base adapted to engage the upstanding side of theright angle member 13. The angle 13 is fixedly disposed upon the wall40a which is normally wide enough to accommodate an L-shaped section 14coextensively disposed with respect to the angle 13. The L-shapedsection is fixedly secured to the top of the wall 40a as shown in FIG. 7so as to provide a horizontal track in which the wheels 31 and 32 may betranslatably, rotatably disposed. The opposite wall is similarlyprovided with an L-shaped section 14 so as to provide a pair ofoppositely disposed tracks, in a horizontal plane, in which theradiation screen may be disposed. As described hereinbefore, a drivecable and driven cable, biased to take up variations in length of theloop of driven cable, are provided to operate the screen.

In those instances where the span of the area to be screened is such asto make the length of a single panel impractical, that is, the width ofa folding screen such as to interfere with the operation of the hinges,plural screens may be used in side-by-side relationship, each operableindependently of an adjacent screen. Where, as for example, in apre-existing structure, two coplanar folding screens are to be used, theoutside edges of the screens are supported in L-shaped track sections 14and the inside edges of each screen are supported in a channel sectionsuspended from the roof structure. The channel section providesside-by-side tracks for the wheels 31 and 32 on the inside edges of thescreens.

As has been mentioned hereinabove, the radiation screen may be installedin inclinedly disposed tracks. It will be apparent that the driven cablemay be adapted to exert sufficient frictional force on the track-guidewheels 32 and 31 so as to permit the screen to remain in an extended, orpartially extended position, though it may be inclinedly disposed. Theprecise extent to which the frictional forces on the wheels may bycontrolled may be varied by increasing the number of flared guides towhich the driven cable is threaded; for example, maximum frictionalforce will be provided by threading the cable through successive flaredguides. A lesser frictional force may be obtained by threading the cablethrough flared guides disposed on every alternate rod carrying a wheel.Even fewer flared guides may suffice where the angle of inclination issmall, that is, in the range from 15 to 30. Additionally, wheels whichhave relatively greater friction coefficients with respect to the rodson which they are disposed may be used to minimize the tendency of thescreen to collapse from an extended, upwardly inclined position. Othermeans for increasing the friction to overcome the tendency of the screento collapse in its inclined tracks due to its weight will be apparent tothose skilled in the art. Depending upon the choice of frictionalengagement of successive panels on the radiation screen, the tracks inwhich the screen is disposed may be inclined from the horizontal at anyangle less than about 75. More preferably, the screen is used at anglesinclined from the horizontal which are less than 45. It will be apparentthat the physical dimensions of the skylight under which the radiationscreen is to be disposed, the number of screens to be used inside-by-side relationship,

8 the width of the skylight and the length of each screen will all befactors in determining the practical limits of the inclination of thetracks in which the screen may operate.

Though in most instances where a screen is to be inclinedly disposed, itwill be extensible upwardly, in some instances, it may be desirable tohave an inclinedly disposed screen which is extensible downwardly, thatis, the screen may be extended essentially under its own weight but mustbe collapsed by returning the panels into their stacked relationship bycollapsing the screen, overcoming the downward component of its weightin the tracks.

In another second embodiment of the invention illustrated in FIGS. 8-10the folding screen may be stored more compactly by a differentdisposition of the arcuate panels in hinged relationship with eachother. This second embodiment also provides for translation of thepanels in a unique by-level track. In the description hereinafterreference will be made only to the details necessary to distinguish thissecond embodiment from the first one, since other details as tooperation will be apparent from the foregoing description of the first.

Referring now particularly to FIG. 8 there is shown a side elevation,with a portion broken away, of a folding screen indicated generally bythe reference numeral having a lead panel 111, intermediate panels 112and pivot panel 113 (see FIG. 9). As will be evident, each panelcomprises an arcuate elongate strip bounded at its edges by thickeneddiscontinuous ribs having an axial bore therethrough, as describedhereinbefore, so that adjacent panels may be interdigitated and hingedat upper hinges 114 and at lower hinges 115. With this arrangement everyother panel is concave upwards, the remaining panels being concavedownwards, and as will be seen in FIG. 9, the collapsed screen is morecompact than the screen with all panels concave downwards.

- Each upper hinge 114 has an upper hinge rod 116 journaled in theinterdigitated ribs of adjacent panels, and each lower hinge has a lowerhinge rod 117 similarly joumaled. Each upper hinge rod 116 has an upperroller 118 rotatably mounted near each end of the rod 1 16, and eachlower hinge rod 117 has a lower roller 119 rotatably mounted near eachend of the rod 117. The lower rollers 119 are always supported but theupper rollers are not supported when the screen is in the closedposition; only some of the upper rollers are supported when the screenis partially open; and all the upper rollers are supported when thescreen is fully extended, as will be better understood from thefollowing description of the support means in which the rollers aretranslated. The rollers reduce friction and are preferred. It will beevident that where the friction to be overcome in opening and closingthe screen is not a factor, or where substantial friction is desired,the rollers may be replaced with any suitable translatable supports suchas pads or spacers fixedly disposed at the ends of the hinge rods.

Referring now to FIG. 10 in particular, there is shown a support beamindicated generally by reference numeral 120, for the screen 110, whichsupport beam also supports the plastic bubble indicated generally bereference numeral 130. The support beam 120 has a web 121 the lowerportion of which includes a box section 122. Flanges 123 and 124 arenormally disposed relative to one another and protrude from the boxsection 122 so the flanges rest on a supporting wall of the structurecovered by the plastic bubble 130. The upper horizontal side 125 of thebox section 122 serves as the lower level support upon which the lowerrollers 119 all translated, and terminates in a lower guide lip 126.Intermediate the guide lip 126 and the web 121, an arcuate member 127projects above the lower roller 119 and terminates in a horizontal ledge128 which serves as the upper level support upon which the upper rollers118 are translated. An upper guide lip 129 on the upper level limitslateral movement of the upper rollers 118.

A similar support means is provided for the oppositely disposed side ofthe screen. As described in the first embodiment, where the span underthe bubble is large, it may be desirable to provide an intermediatebi-level track in which the rollers are translatable. As also describedhereinbefore, suitable pulleys and drive cables, previously used, areoperatively connected to the lead panel 111 of the screen asdiagramatically illustrated herein, so that pulling on the lead panelprogressively moves the upper rollers 118 into rolling engagement withthe horizontal ledge or upper level of the bi-level tracks.

For example, a drive cable 131 may be drivingly trained upon a pulley132 and attached to the leading edge of the folding screen to enable thescreen to be extended and collapsed by exerting a force on the leadpanel. Thus, it will be appreciated that the lead panel and the nextadjacent panel are extended or collapsed first, with the remainingpanels successively performing the same movement. The screen may thus bepartially extended, the remaining portion remaining in a collapsedposition. The pulley 132 may be affixed to a structural member as shownin FIG. 8. A second pulley 133 is similarly affixed at the opposite endof the screen adjacent the pivot panel 113 as shown in FIG. 10. Thedrive cable 131 is drivingly trained upon the pulley and anchored to thesupport 134 in which a pivot rod for the pivot panel is journaled. Itwill be evident that the length of the loop defined by the drive cable131 and the folding screen 110 will vary depending upon the extent towhich the screen is extended. When the screen is fully extended, thereis maximum slack in the drive cable, and all upper rollers 118 aresupported on the upper level of the bi-level track. It is desirable,particularly for motor-driven operation of the screen, that a take-uploop be provided for such slack as does occur depending upon theposition of the screen, and this take-up may be effected by any meanssuch as are well known in the art.

The scope of the invention is not limited to the slavish imitation ofall of the structural and operative details mentioned above. These havebeen given merely by way of an example of a presently preferredembodiment of the invention. For example, though rolling means have beendescribed for the obvious reason that in most installations, rollingfriction is preferable, it will be apparent that the wheels in thetracks may be replaced by pads which are slidably disposed in tracks.

I claim:

1. A folding radiation screen having predetermined permeability tosunlight, for operation beneath a skylight or light-permeable roofstructure, said screen comprising a plurality of relatively rigid panelssuccessively hinged together through interdigitated longitudinal edgesthereof for co-action in side-by-side relationship and supported by apair of parallel, overhead track means inclinedly disposed at an angleless than with respect to the horizontal, each said track meansincluding a lower horizontal track and an immovable vertical guiding lipmeans, said panels being movable from a folded, stacked relationshipadjacent one end of said track means to a generally planar relationshipextending between said one end and the other end of said track means,the end panel adjacent said one end being fixedly disposed for pivotalmovement about the longitudinal edge of said end panel adjacent said oneend; rolling means supported by said lower horizontal track, and, washeror spacer means supported by said lip means to coactingly translate saidpanels along said tracks so as to dispose hinged edges supported by saidlip means in a plane vertically upwardly displaced rela tive to a planeincluding hinged edges supported by said rolling means; and, flexiblemeans to exert a sufficient force on said panels, in either directionalong said tracks, to translate said panels from said stackedrelationship into said generally planar relationship, or vice versa, soas to control the intensity of said sunlight below said screen.

2. The folding screen of claim 1 wherein said panels are arcuate, thecurvature of each panel being such that a line parallel to thelongitudinal axis of each panel and on the surface thereof, isvertically displaced with respect to the longitudinal edges of eachpanel.

3. A folding radiation screen having predetermined permeability tosunlight, for operation beneath a skylight or light-permeable roofstructure, said screen comprising a plurality of relatively rigid panelssuccessively hinged together through interdigitated longitudinal edgesthereof for co-action in side-by-side relationship and supported by apair of parallel, overhead bilevel track means inclinedly disposed at anangle less than 75 with respect to the horizontal, each said track meansincluding an upper level track and a lower level track, said panelsbeing movable from a folded, stacked relationship adjacent one end ofsaid track means, to a generally planarrelationship extending betweensaid one end and the other end of said track means, the end paneladjacent said one end being fixedly disposed for pivotal movement aboutthe longitudinal edge of said end panel adjacent said one end; upperroller means supported by said upper level track, and lower roller meanssupported by said lower level track to coactingly translate said panelsalong said tracks so as to dispose upper hinges of said screen in aplane vertically upwardly displaced relative to a plane including lowerhinges of said screen; and, flexible means to exert sufficient force onsaid panels, in either direction along said tracks, to translate saidpanels from said stacked relationship into said generally planarrelationship, or vice versa, so as to control the intensity of saidsunlight below said screen.

4. The folding screen of claim 3 wherein said panels are arcuate andsuccessively hinged together with a downwardly concave panel adjacent anupwardly concave panel.

1. A folding radiation screen having predetermined permeability tosunlight, for operation beneath a skylight or light-permeable roofstructure, said screen comprising a plurality of relatively rigid panelssuccessively hinged together through interdigitated longitudinal edgesthereof for co-action in side-by-side relationship and supported by apair of parallel, overhead track means inclinedly disposed at an angleless than 75* with respect to the horizontal, each said track meansincluding a lower horizontal track and an immovable vertical guiding lipmeans, said panels being movable from a folded, stacked relationshipadjacent one end of said track means to a generally planar relationshipextending between said one end and the other end of said track means,the end panel adjacent said one end being fixedly disposed for pivotalmovement about the longitudinal edge of said end panel adjacent said oneend; rolling means supported by said lower horizontal track, and, washeror spacer means supported by said lip means to coactingly translate saidpanels along said tracks so as to dispose hinged edges supported by saidlip means in a plane vertically upwardly displaced relative to a planeincluding hinged edges supported by said rolling means; and, flexiblemeans to exert a sufficient force on said panels, in either directionalong said tracks, to translate said panels from said stackedrelationship into said generally planar relationship, or vice versa, soas to control the intensity of said sunlight below said screen.
 2. Thefolding screen of claim 1 wherein said panels are arcuate, the curvatureof each panel being such that a line parallel to the longitudinal axisof each panel and on the surface thereof, is vertically displaced withrespect to the longitudinal edges of each panel.
 3. A folding radiationscreen having predetermined permeability to sunlight, for operationbeneath a skylight or light-permeable roof structure, said screencomprising a plurality of relatively rigid panels successively hingedtogether through interdigitated longitudinal edges thereof for co-actionin side-by-side relationship and supported by a pair of parallel,overhead bi-level track means inclinedly disposed at an angle less than75* WITH respect to the horizontal, each said track means including anupper level track and a lower level track, said panels being movablefrom a folded, stacked relationship adjacent one end of said trackmeans, to a generally planar relationship extending between said one endand the other end of said track means, the end panel adjacent said oneend being fixedly disposed for pivotal movement about the longitudinaledge of said end panel adjacent said one end; upper roller meanssupported by said upper level track, and lower roller means supported bysaid lower level track to coactingly translate said panels along saidtracks so as to dispose upper hinges of said screen in a planevertically upwardly displaced relative to a plane including lower hingesof said screen; and, flexible means to exert sufficient force on saidpanels, in either direction along said tracks, to translate said panelsfrom said stacked relationship into said generally planar relationship,or vice versa, so as to control the intensity of said sunlight belowsaid screen.
 4. The folding screen of claim 3 wherein said panels arearcuate and successively hinged together with a downwardly concave paneladjacent an upwardly concave panel.